For example, in Java 8, the bootstrap class loader was located in the Java Runtime Environment’s rt.jar file. ... and classes loaded by a child class loader are not visible to parent class loaders.

When two classes are related through inheritance, the child class must be able to access every accessible field, method, or constructor of its parent class. In Java, we use the reserved word super ...

Sealed classes make Java an even more powerful and expressive language and set the stage for even more sophisticated techniques such as pattern matching, which we'll explore in a subsequent article. A ...